World War Ooo
by Fauned
Summary: Ooo is at war after Prince Gumball is possessed by The Lich - Marshall Lee, Flame Prince and Fionna band together to restore the land into order. Fionna realises that she maybe she doesn't have to fight alone any more, but who will she choose to fight by her side? Fionna x Marshall Lee
1. Under attack

Quick info!

The land of Ooo is at war after Prince Gumball is possessed by The Lich and uses his power to create an army of darkness. Citizens who are possessed are much like the Goo monsters in Adventure time but stronger and more menacing. The land has been split into groups hiding or fighting against the reign of evil.

Not that confident with my writing yet. Hope you like it!

:3

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Chapter One

At night the river would glow - the toxic waste that flowed in the water bright enough to bathe the ground with a soft emerald for a remarkable distance, almost to the point where it was appealing to those who forgot about the poison that menaced the stream. The light caught the muslin wings of brave insects that dared to fly close to the glow before fleeing back into the safe cover of darkness.

Marshall watched the insects from his own bit of shade, wondering how they knew what distance was just enough for them to not feel the dizzying effects of the gas in the air that billowed from the water - and if they had watched others get too close and drop to the ground. Ever since the Candy Kingdom had turned it was dangerous to come close to the rivers of Ooo; they attracted and spawned hellish creatures that lurked by the sides, hoping to drag innocent citizens into the depths to consume and grow from their matter. Marshall pushed his hand under his shirt collar to wipe the back of his neck as he recalled seeing candy people being pulled into the river by demons and spat out as devils.

He smiled absently - he felt no threat from these creatures. They were stupid and slow, no match for his quick movements and power. He kicked off from the ground and floated away from the river. The smell of the Candy Kingdom reached him before he could even see it. It smelt rotten yet sickly sweet due to the burned walls that oozed with blackened gunk from the countless resistance movements that had tried to save Gumball and the Candy people. Stopping by a rock, he peered over the stone at the greyed banana guards that stood along the wall.

"Feeling sentimental, are we?"

Marshall Lee felt the heat on his cheek as Flame Prince advanced from around the rock. He felt a little twinge of annoyance that he hadn't noticed the Prince sooner - he was made of fire, after all.

"Nah, it could burn to the ground for all I care. Wasn't supposed to be here in the first place." Marshall retorted, floating a few paces back so that the glare from Flame's body wasn't so sudden and painful to his dark-loving pupils.

"I don't think any of us are supposed to be here," Flame replied, coolly. Marshall hated to admit it but Flame Prince was really an impressive presence - his hair tapered to a sharp tip that would only be a spectacle on anyone else and yet he radiated this energy that made him almost impossible to look away from. Marshall narrowed his eyes as he ignored a flick of jealousy. "Yet we are here anyway. What brings you so far from your cess pit?"

"You know me - death, misery, destruction, I live for it," Marshall smirked.

Flame Prince raised his eyebrow. "Marshall, you're dead. I don't think you live for anything.'

The vampire king opened his mouth to protest, but closed it when he realised the Flame Prince had a point. Flame noticed his hesitation and his sharp face spread into a smug grin. They stood in silence for a minute, watching the smoke rise from the Candy Kingdom that reared before them. Marshall realised that it had been a few months since he had last seen Flame Prince; the usual guests of the Candy balls had been split apart by the war - those who were possessed joined the hoarde and those who fled formed factions across the land. There were those that stayed in hiding and those, like Flame Prince, who chose to fight.

"I just came to see what's going on. It's good to stay informed - you know?" Marshall finally said, resting his arms behind his head.

Flame Prince guffawed. "It's good to fight! Why waste time just watching the world go to ruin? You should be ashamed, you coward."

Marshall rolled his eyes. "Look, Flame, I've been around for so long and I know when a battle is lost. Only time will right this one, and, hell - I've got all the time in the world."

The fire creature became bright with anger and Marshall tried his best to ignore the increased temperature that licked his skin. It was true, Flame Prince was young and he was old, too old for Wars and too old for arguments with kids. He smiled, suddenly - maybe not too old for arguments with THIS kid.

Marshall Lee leaned close to Flame Prince and blinked very slowly, almost dotingly. "Don't worry, Flame. One day you'll understand." He raised a hand and flicked it at the wrist so his palm was under Flame's nose. "You're just too, well, young."

He floated back a few yards as Flame burned up so quickly Marshall was a little worried he had singed the front of his hair.

"I AM NOT TOO YOUNG!" Flame seethed, the rock wall suddenly covered with soot from his incensed fury.

Marshall smirked. "I am over a thousand years older than you, kid, I think I know a child when I see one."

Flame Prince burned brighter. "YOU ARE A COWARD!"

"Whatever you say, kiddo."

"I AM OLD ENOUGH TO FIGHT!"

"Can you even lift a sword?"

Flame Prince was glowing so hot he was almost white. His eyes had become slits that stared at the vampire and his voice lowered so that Marshall could barely hear it over the roar of the fire.

"I hate your stupid hipster shirt."

Marshall instinctively bared his fangs. "Now hold on a sec-"

There was a sudden screaming sound which caused Flame Prince to sharply reduce in size and heat, the boys looked at each other and then back towards the source of the sound. It was in the direction of the mountains where the ground got darker and rockier. Marshall and Flame both started speeding towards the source, Marshall shooting a foul look in Flame's direction as the Prince easily kept up with him on foot when faced with Marshall's flight speed.

The sound of metal making contact was loud and frantic. Goo monsters had filled the ravine - not the tame creatures that lived by sucking the earth after the first War, but powerful mutations whose strength could rival Marshall's even when feral. They leaked a toxic gunk that would claim whoever came into contact with it, emptying the host and filling them entirely with a mindless intent to feed. Marshall floated for a moment, considering whether to turn away from the hoarde, before noticing the point to where the monsters were gravitating.

A girl, drowned in her cloak and almost doubled over, was backing against the wall of the doomed ravine, swinging her sword in front of her in slow, desperate movements. The action was laboured, as if pained, and the sword sliced through one of the monsters, causing it to moan and fall to the floor. The girl's triumphant laugh was cut short when two more monsters took it's place. She managed to hold back another two before a large sphinx with gunk pouring from it's eyes sprinted forwards with a roar, trampling over the smaller monsters to claim it's prey.

"Not today!" She snarled. "You'll never have me!"

Marshall swore under his breath.

Flame Prince had run towards the scene and dived in the middle of the hoarde, suddenly growing a few miles bigger and roaring with the heat of a volcano. The Goo monsters shrunk back in fear of the sudden hot energy, falling over themselves to shrink back to the shadows. The sphinx was large enough to bound out of the path of his fire and was a few yards from the girl. She dropped her sword.

Marshall towered over her in his demon form, shrieking as his fur sprouted all over his growing arms and licking his terrifying fangs before swiping at the smaller sphinx with his sharp claws, flexing his wings to demonstrate his size. The sphinx got the message and lumbered backwards, following his hoarde into the safety of the night, leaving behind a stream of toxic waste that had fallen like tears from it's eyes.

Still in demon bat form, Marshall turned towards the girl and went to pick her up in his huge claw, the movement a little too strong causing her to yelp in pain as she was knocked off her feet. Hearing her yelp, Marshall began to decrease in size until he was normal again, his shirt a little loose on his chest; he held the girl in his arms and soon realised she was unconscious. Raising his thin hand he ran his fingers over the soft fabric of her cloak, and, slowly, pulled it over her head to reveal a cascade of golden hair that fell to his feet. His heart jumped when he realised she had opened her big eyes and was watching him observe her.

"You are so ugly as a giant bat," She moaned, burying her face in his chest before passing out again.

He narrowed his eyes and hissed. "I should have known it was you."

Waiting for a response and getting none, he dropped her sleeping body on the floor with a painful thud.

I hope that hurt, he thought.


	2. Under a roof

Chapter Two

Fionna felt the cold floor against her face before she opened her eyes. Two stern voices danced in the air around her, but they were drowned out by the sharp pain that the girl could feel searing up her right arm. Rolling onto her back, she buried her arm in her cloak and opened one lid at a time, groaning at the memories that were flooding to her brain. She was angry at herself for letting the monsters get the better of her, gritting her teeth with frustration. Realising she wasn't alone, she looked, surprised, at the two figures that were yelling at eachother across the room. The deco was simple and weirdly homely - it was Marshall Lee's house, she frowned.

"Why do you have to be such a baby?" Flame Prince was arguing. "It is just for a few days."

"You're the baby!" Marshall was hissing. He was sat on the edge of his sofa, his back so stiff that he looked like he was ready to leap from his perch at any moment. "I don't want to babysit some kid for an hour, let alone a day! Why can't she stay with you?"

"What, and trust the Fire People with her? The Fire Kingdom isn't a place for human girls, Marshall. You know that."

"Neither is my HOUSE, Flame," Marshall hissed, his fangs pressed so hard into his bottom lip they left tiny, black holes.

Fionna watched them for a while from her spot on the floor, a little irritated that she was in a heap on the floor whilst Marshall was sat upon the sofa. It had been a few years since she had seen him last, as she had devoted herself to defending the citizens of Ooo from the evil that had claimed the land, and she mentally sized up this Marshall with the Marshall that was unaffected by the War. He looked the same; dressed in laid-back, scruffy clothes, his black hair probably unbrushed for a decade and very close to hanging over his eyes. His brow was lower, his scowl more permanent, and his shoulders were fixedly raised. Considering he didn't age, Fionna felt that he was somehow less boyish, but she couldn't figure out why.

"I need to fight for the Kingdom, you cowardly dog!" Flame Prince barked. "She is staying with you!"

Marshall stood up abruptly. "I-"

"Both of you SHUT UP!" Fionna yelled, jutting out her bottom jaw in anger. She propped herself up with one arm and made sure to hide the other whilst slowly getting to her feet and marching to the two boys, who stood in shock. Her hair was loose and flowing behind her like a golden veil, a few strands hanging stubbornly in front of her face. "I can fight, and none of you chumps are gonna keep me here!" She pointed a finger defiantly at Flame Prince. "And where is my hat?"

Flame Prince opened his mouth in surprise.

The Vampire King moved towards her quickly, appearing abruptly next to her face and she startled at the suddenly closeness of the boy. She yelped in pain and looked down; Marshall had grabbed the arm that was hidden in her cloak and yanked it free from the material, pulling it up in front of his eyes. She squirmed but her own wriggling put more pressure on the arm so she stopped as soon as she had started, letting her other arm go limp by her side and looking at her feet in shame.

"Did you think none of us would notice this?" Marshall growled. "You think you can fight with this?" Fionna didn't look up from her shoes. "Give me a break." He said, placing his fingers on her wrist and slowly tracing them up her arm, moving her sleeve delicately up to the elbow. She shivered at the touch.

Flame Prince inhaled a sharp breath of air before rubbing his hand through his fiery hair. Fionna's right arm was blackened, green in some places, with dark bruises growing under the skin like malignant roses. She closed her eyes - a Goo monster had cornered her during the fight and she had let it get too close. She had failed. Fionna refused to open her eyes due to the tears that she felt burning behind her eyelids.

"Let me see," Flame Prince said, softly, pushing Marshall to the side so hard that he was sprawled on the sofa with a snarl. He brought his hand delicately to her arm but stopped just before they made contact, hovering his palm over the blistering skin as a light to help him see closer. Fionna peeped at the Prince's face, which was twisted in concentration and concern whilst examining his patient.

"It's no use," he said, motioning for her to drop the arm (which she did, gratefully). "I'm no Gumball, but that thing is a problem for us and more importantly, for you." He looked her deep in the eye. "That poison is going to spread, Fionna, and when it does-"

The girl turned her face stubbornly. "That won't happen," she lied.

They all looked at the floor in silence.

"Well then," Flame Prince clapped his hands together. "That's my cue to leave."

"What?!" Marshall and Fionna snapped, scowling.

Flame Prince had moved to the door by this point. "Someone needs to go and find an antidote or something for that infection. I'm gonna be the one to find it." He grinned back at the pair. "I'll be quick - just gotta break into the Candy Kingdom and sneak past evil Gumball to get to his potions. Kids stuff."

Fionna jumped when Marshall let out a hiss and stomped over to Flame Prince. "Flame, you _are _a kid, and if you didn't notice I am a vampire KING. I'll go to Gumball."

Flame Prince laughed. "You're a KING?" Marshall frowned. "Start acting like one." Flame Prince let out a small jet of fire that flew through the air towards the boy, causing him to fly backwards into Fionna who yelped when he brushed her arm. Marshall turned around in surprise and reached to touch her arm before stopping himself, blushing. Fionna saw the guilt in his eyes and raised her eyebrows.

"Two days, tops!" Flame Prince crowed. By the time the pair looked up, he had disappeared.

The boy looked back at Fionna, who looked up eagerly in his eyes to search for the flicker of humanity that she had just seen. He stared back for a minute before scoffing and brushing past her good side towards the door.

"Do whatever you want - just stay out of my room." He said. "I suggest you take a bath." She thought she saw him smile but as he turned she realised it was a very violent grimace.

"You stink."


	3. Under the weather

Chapter Three

The vampire king rolled over as he opened his eyes, blinking the sleep away in the darkness and stretching his arms. The boy stared at his bed below him, messy, the blanket shredded, and slowly came to the realisation that he had floated to the ceiling in his sleep again. Sighing, and cursing the fact that he would need a new blanket, he decided to ignore the signs of stress that he must be feeling.

Descending from the ceiling, he floated lazily to the bathroom, stopping before the door. He could feel the steam from the shower radiating from the wood, and pressed his forehead against the frame.

"Fionna?" He groaned. "Are you gonna be long? I don't have the patience for you to be braiding your hair and painting your nails or whatever."

"I'm just having a shower," came the annoyed response. "And if I want to do those things, I will. Now leave me alone."

Marshall rolled his eyes back into his head for a full minute before heading towards the kitchen. As it turned out, he and Fionna shared a hatred of mornings with a passion, which fueled an immense hatred for other people at that particular time of day. Her nasal voice swam in his brain like a parasite, eating away at his patience so much that his predator instincts told him repeatedly to bite her and get it over with. He walked to the fridge, and again pressed his head against the door in frustration. It would be so worth it, he thought, smiling to himself. He could feel the red swirling around her body sometimes, her supple body that had grown nicely since he had known her before the War, all plumped out with red in all the right places. Even now he could sense the red, heated up from the shower, waiting for him, collecting in that meaty thigh of hers.

"No, no, no, no," he murmered, opening the fridge and grabbing a handful of strawberries, draining the colour in a matter of seconds. "You're just hungry."

He collapsed in the kitchen chair and rubbed a hand over his black hair. "Not cool."

After a few minutes to settle, the hunger passed and Marshall realised that Fionna was singing. Her voice was childish, he smirked, but in tune, so he picked up his guitar and began to play a few notes to match her melody. Who sings in the shower anymore, he thought, tapping his foot to his song. His mind wandered over her silly face, puffy from the shower, and her long hair wet trailing down her spine, clinging to the curve of her hip and hugging the small of her back. He stopped playing. I'm not even hungry, he thought, shaking his head in disbelief.

Was that a scream? He concentrated his hearing.

"Fionna?!" He yelled, flying to the door in a manner of seconds and trying the handle, which was locked. "Fionna, are you ok?"

"Yeah, I-I'm fine," came the response, strained. "I slipped in the shower. I'm f-fine."

Marshall narrowed his eyes, listening to her breathing through the wood.

"Just leave me alone. Don't come in!" She whined. Marshall hung back for a second before his ears picked up a sudden change in breathing, her breaths getting faster until they culminated into a small squeak. In one kick he had the door swinging from the hinge, causing Fionna to shrink in surprise from her seat on the floor in the middle of the bathroom, her body sitting on her knees clad in white towel. Her eyes peeked through the curtain of wet hair that was hanging over her face and Marshall was struck by the look of fear that reflected back at him before noticing the long scratches that ran down her left shoulder, little rivers of blood collecting in a pool at her elbow.

"Fionna what have you -?" He asked, bewildered and nervous, rushing towards her to do anything to stop the fear that was sharp in her expression. The girl shrunk away from him, doubled over and grimacing.

She was holding her arm. "I don't know how to stop it." She growled, with a surprising amount of anger. "I can't stop it."

Marshall could only see her left side but breathed in sharply when he noticed her right arm, the black bruises had grown even bigger since he had last seen her bare skin, perhaps even penetrating the skin from underneath to ooze a strange liquid that shimmered in the light. It looked mottled, like rotting flesh. "What do you mean? Be more clear."

"My arm," she growled, again. "Every time I stop focusing I just - I don't know." Her voice lowered to a whisper. "It moves by itself."

At that, her arm lurched towards her neck and the nails dug into the skin, slowly dragging down towards the left shoulder leaving little canyons of red. The girl screamed in pain but the movement did not stop, tipping over the bend in her shoulder towards the same arm that had received punishment minutes earlier.

"Dude!" Marshall barked, rushing forwards to pull the arm down, having to use more strength than he expected to yank the arm behind her back and locking her body between his legs to achieve the optimum holding position. Her feet kicked and pushed against the floor in surprise, pressing her body tight into the curve of the boy's torso and yelped when he pressed his arm over her collarbone to keep her there.

They struggled for a minute before their breaths aligned with eachother. Marshall could feel Fionna's heart beating through her back, his grip still so tight that his face was buried in the groove of her neck.

"Marshall Lee, you can let go of me now," Fionna whined. "I think I'm ok."

"I don't wanna risk it," he murmered into her neck. "Why didn't you tell me about this? Do you think it's the infection? Dude, this is messed up. I don't even know how to deal with this stuff."

She scoffed. "You don't have to deal with it. I can handle it by myself."

"Clearly. Look at you, you're bleeding everywhere. You practically carved yourself up as a Sunday lunch."

"Get off me!" She yelled, struggling again. Marshall tightened his grip against her collarbone and she quickly stopped resisting with a sigh of irritation.

"Marshall?" Her voice was small, he thought, and girlish. "Do you remember when we used to hang out all the time? Before all this stuff happened in Ooo?" He made a small noise in response; thinking back to the times when he would creep up on the little chubby girl in the white hat and laugh when he made her mad, all before they would go to their homes at night and snuggle up with a blanket knowing that they would be safe whilst they slept, and still safe in the morning. He smiled.

"Do you remember when I cried about Gumball saying that he liked girls with brown hair? Geez, I was such a kid back then." Her laughs were light, and beat against Marshall's chest.

"Yeah," he replied, "you're a bit of a loser sometimes."

"Shut up." She snapped. "What I'm saying is - do you remember putting some weird dye in Gumball's shampoo that turned his hair into worms that crawled off of his head? We spent hours trying to chase all the worms to fix it. And then you two got into a fight and I took his side and punched you in the face for being such a creep? I didn't understand it but you told me after I punched you that it didn't matter if my hair was blonde or brown or made of worms, Gumball still wouldn't deserve a five minute date with me."

Marshall felt a sweeping wave of embarrassment and was very thankful that she couldn't see his expression. "Uh, yeah, I guess," he muttered. "What are you getting at?"

"I just wanna go back to being a kid," she blurted. "I want my biggest problem to be that some dude doesn't like the colour of my hair - not that I have an arm that is trying to kill me and will one day consume my entire body!" He felt the girl wither in his arms. "I'm not a kid anymore, and that really sucks."

Fionna's body loosened and relaxed against Marshall's so that he could suddenly feel every inch of her against his body. From his position behind her, he pulled the arm that he was holding further behind her back so that she swung sideways an inch to be able to look at her in the eye, almost a little pleased to see the soft, dreamy look that had covered her face.

"You're right." He smirked, receiving a confused turn of the head from Fionna. Boldly, and for no real reason, he gave a suggestive glance down at the towel that concealed Fionna's body - which was beginning to look a little loose around the sides. "You stopped being a kid quite some time ago."

Marshall Lee watched her stomp out of the room from his position on the floor, rubbing his eye where she had just punched him with absolute rage in his smug face.

He definitely deserved it.


End file.
